US20100157976A1 - Network device - Google Patents
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- US20100157976A1 US20100157976A1 US12/088,706 US8870606A US2010157976A1 US 20100157976 A1 US20100157976 A1 US 20100157976A1 US 8870606 A US8870606 A US 8870606A US 2010157976 A1 US2010157976 A1 US 2010157976A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
- H04M11/066—Telephone sets adapted for data transmision
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Abstract
Description
- The present invention relates to network devices and particularly to network devices capable of switching a connection status of a telephone line.
- Recently, Internet Protocol (IP) network call service utilizing an IP increasingly spreads. Accordingly a technique to switch where to connect a telephone selectively between an IP network and a public network is indispensable. (This technique will hereinafter also be referred to as “the switching technique”.) A public network, as referred to herein, indicates public switched telephone networks (PSTN).
- Such techniques are disclosed in Japanese Patent Laying-open Nos. 2004-007314 (Patent Document 1), 2005-005875 (Patent Document 2), and 2005-086286 (Patent Document 3).
- Japanese Patent Laying-open No. 2004-007314 (Patent Document 1) discloses that a telephone rate table previously prepared as based on telephone numbers is used to switch where to connect a telephone selectively between an IP network and a public network.
- Japanese Patent Laying-open No. 2005-005875 (Patent Document 2) discloses connecting a telephone, as switched in response to a calling signal of a telephone network or an IP network, and connecting the telephone to the telephone network when a power failure occurs.
- Japanese Patent Laying-open No. 2005-086286 (Patent Document 3) discloses that when a power failure is detected, the power of a public network is used to dial from a telephone network to the person that had been calling before the power failure to resume the call.
- A public network in general allows a maximum of two calls with a single cable, while an IP network allows three or more calls with a single cable.
- However, a call over the IP network requires power, and when a power failure occurs, the call over the IP network cannot be made. Accordingly, a conventional communication device that employs the EP network to make a call is adapted to switch where to connect to a public network at a power failure to allow the call to continue even at the power failure.
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FIG. 8 is a block diagram showing an internal configuration of aconventional network device 10000 capable of switching a communication line. With reference toFIG. 8 ,network device 10000 includescommunication units communication units Communication units Communication unit 210A is connected by the analog telephone line to ananalog telephone 100A.Communication unit 210A has a function determining whetheranalog telephone 100A is on the hook or off the hook.Communication unit 210C is connected over apublic network 70C to ananalog telephone 100C. -
Communication units Communication unit 210B is connected over anIP network 70E to a Voice over Internet Protocol (VoIP)telephone 100B. Note thatcommunication unit 210B may be connected through a LAN cable directly toVoIP telephone 100B.Communication unit 210D is connected over anIP network 70D to aVoIP telephone 100D. Note thatcommunication unit 210D may be connected through a LAN cable directly toVoIP telephone 100D. -
Network device 10000 further includes acontrol unit 230, a line interface unit (LIU) 222, a subscriber line interface circuit (SLIC) 224, and aswitch unit 240. -
Control unit 230 has a function controlling each component innetwork device 10000. Furthermore,control unit 230 has a function communicating data with each component innetwork device 10000. - LIU 222 is a circuit having a function for connecting to
public network 70C in response to an instruction issued fromcontrol unit 230. Furthermore, LIU 222 has a function performing a process for receiving a calling signal frompublic network 70C, a process for receiving a telephone number of an originator overpublic network 70C, a process for generating a dial number, an audio process, and the like. - SLIC 224 has a function generating a pseudo public network. This allows a calling signal to be transmitted to
analog telephone 100A connected tocommunication unit 210A. Furthermore, SLIC 224 has a function performing a process for generating a telephone number of an originator, a process for receiving a dial signal from a telephone, an audio process, and the like. - In the following description, a signal and a signal line have binary, high voltage (i.e., voltage Vcc) and low voltage statuses also referred to as an “H level” and an “L level”, respectively.
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Switch unit 240 has a function switching, in response to a switch control signal transmitted fromcontrol unit 230, where to connectanalog telephone 100A connected tocommunication unit 210A betweenpublic network 70C andIP network 70D. More specifically,switch unit 240 has a function electrically connectingcommunication units switch unit 240 has a function electrically connectingcommunication unit 210A and SLIC 224 together when the switch control signal has the H level. - Furthermore,
switch unit 240 electrically connectscommunication units power supply unit 320 for a system, which will be described later, does not supply an operating voltage (Vcc). Furthermore,switch unit 240 has a function such that when the operating voltage supplied frompower supply unit 320 for the system described later decreases,switch unit 240 electrically connectscommunication units -
Network device 10000 further includes apower supply unit 300.Power supply unit 300 includes anAC adapter 310, andpower supply unit 320 for the system.AC adapter 310 receives an alternate current voltage supplied from an AC power supply, converts the received alternate current voltage to a direct current voltage of a predetermined level (for example of 5V), and supplies the direct current voltage topower supply unit 320 for the system. -
Power supply unit 320 for the system receives the direct current voltage fromAC adapter 310.Power supply unit 320 for the system supplies each component (e.g., switch unit 240) internal tonetwork device 10000 with operating voltage Vcc. In other words, each component innetwork device 10000 operates on operating voltage Vcc. -
Network device 10000 can concurrently perform a process for a call betweenanalog telephone 100A andVoIP telephone 100D and that for a call betweenanalog telephone 100C and VoIP telephone 10013. In other words,network device 10000 allows a plurality of processes for calls, respectively, to be concurrently performed. In this case,analog telephone 100A can have a call withVoIP telephone 100D via a first call path defined bycommunication unit 210A,switch unit 240, SLIC 224,control unit 230,communication unit 210D andIP network 70D. Furthermore,analog telephone 100C can have a call withVoIP telephone 100B via a second call path defined bypublic network 70C,communication unit 210C, LIU 222,control unit 230,communication unit 210B andIP network 70E. When the first and second call paths are concurrently used and if in that condition a power failure occurs (i.e. the power topower supply unit 300 decreases),network device 10000 performs a process to switch where to connectanalog telephone 100A fromIP network 70D topublic network 70C. More specifically, when the operating voltage supplied frompower supply unit 320 for the system decreases,switch unit 240 electrically connectscommunication units - Thus a process will be performed such that
analog telephone 100A uses the power ofpublic network 70C to have a call withanalog telephone 100C via a third call path defined bycommunication unit 210A,switch unit 240,communication unit 210C andpublic network 70C. More specifically, when the first and second call paths are concurrently used and if in that condition a power failure occurs,conventional network device 10000 disadvantageously causesanalog telephone 100A having a call withVoIP telephone 100D to unintentionally become communicable withanalog telephone 100C. - This is attributed to a property of a line of a public network. To disallow a signal to be communicated between
public network 70C andanalog telephone 100C connected topublic network 70C, it is necessary that a line serving as a path extending betweenanalog telephone 100C andVoIP telephone 100B have an on-hook status detected for at least one second. In the following, a period of time required to disallow a signal to be communicated between a public network and an analog telephone connected to the public network will also be referred to as a “period of time required to disable public network communication”. - Thus for example if a power failure or the like occurs, and LIU 222 no longer operates and a line serving as a path connecting
analog telephone 100C andVoIP telephone 100B together is disconnected,switch unit 240 operates as described above to connectcommunication units analog telephone 100A andanalog telephone 100C are off the hook,analog telephone 100A is disadvantageously, unintentionally connected toanalog telephone 100C. - The present invention has been made to overcome the above described disadvantage, and it contemplates a network device capable of preventing unintentional line connection between a plurality of telephones.
- To resolve the above disadvantage, the present invention in one aspect provides a network device having a plurality of telephones each connected thereto over a public network or an Internet network or directly, including: a switch unit for switching where to connect a first telephone of the plurality of telephones between the public network and the Internet network, the first telephone being connected directly to the network device; and a power supply unit for supplying the switch unit with an operating voltage for operating the switch unit, wherein: the power supply unit is capable of supplying the operating voltage for a predetermined period of time as counted from when a device operating voltage supplied to operate the network device is no longer supplied; of the plurality of telephones, a second telephone is connected over the public network to the network device; of the plurality of telephones, a third telephone is an Internet telephone; and the switch unit includes an erroneous connection prevention unit preventing the first and second telephones from becoming communicable with each other when the second and third telephones are communicable with each other and if in that condition the network device is no longer supplied with the device operating voltage.
- Preferably, the third telephone is connected over the Internet network to the network device, and after supplying the network device with the device operating voltage starts, the erroneous connection prevention unit connects the first telephone to the Internet network if the first telephone is disconnected from the public network.
- Preferably, the public network disallows a signal to be communicated between the public network and the second telephone when a path connecting the second and third telephones together is on the hook for a specified period of time shorter than the predetermined period of time, and when the second and third telephones are communicable with each other, and the network device is no longer supplied with the device operating voltage, then after the network device is no longer supplied with the device operating voltage when the predetermined period of time elapses the erroneous connection prevention unit connects the first telephone to the public network.
- Preferably, the third telephone is connected over the Internet network to the network device, and after supplying the network device with the device operating voltage starts, the erroneous connection prevention unit connects the first telephone to the Internet network if the first telephone is disconnected from the public network.
- Preferably, the public network disallows a signal to be communicated between the public network and the second telephone when a path connecting the second and third telephones together is on the hook for a specified period of time shorter than the predetermined period of time, and when the public network and the second telephone cannot communicate a signal therebetween and if the network device is no longer supplied with the device operating voltage, then after the network device is no longer supplied with the device operating voltage the erroneous connection prevention unit connects the first telephone to the public network.
- Preferably, the third telephone is connected over the Internet network to the network device, and after supplying the network device with the device operating voltage starts, the erroneous connection prevention unit connects the first telephone to the Internet network if the first telephone is disconnected from the public network.
- The present network device can prevent a first telephone connected to the network device and a second telephone connected to the network device over a public network from becoming communicable with each other when the second telephone and a third telephone which is an Internet telephone are communicable with each other and a device operating voltage for operating the network device is no longer supplied.
- The present network device can thus effectively prevent unintentional line connection between a plurality of telephones.
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FIG. 1 is a block diagram showing an internal configuration of a network device in an embodiment. -
FIG. 2 is a block diagram showing an internal configuration of a status holding unit. -
FIG. 3 shows an operation table. -
FIG. 4 is an operation waveform diagram, by way of example, for illustrating how the network device operates. -
FIG. 5 is an operation waveform diagram, by way of example, for illustrating how the network device operates. -
FIG. 6 is a flowchart of a process performed to determine public network connection. -
FIG. 7 is a flowchart of a process performed to connect an EP telephone line. -
FIG. 8 is a block diagram showing an internal configuration of a conventional network device capable of switching a communication line. -
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- 70C: public network, 70D, 70E: IP network, 230: control unit, 240: switch unit, 322A: power supply unit for switching, 320A: power supply unit for system, 400: status holding unit, 1000: network device
- Hereinafter reference will be made to the drawings to describe an embodiment of the present invention. In the following description, identical components are identically denoted. Their names and functions are also identical. Accordingly, they will not be described repeatedly in detail.
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FIG. 1 is a block diagram showing an internal configuration of anetwork device 1000 in the present embodiment. With reference toFIG. 1 ,network device 1000 differs from theFIG. 8 network device 10000 in that the former further includes astatus holding unit 400, and apower supply unit 300A rather thanpower supply unit 300, and thatcommunication unit 210A communicates data withcontrol unit 230. The remainder is similar to that ofnetwork device 10000, and will not be described repeatedly in detail. -
Power supply unit 300A differs from theFIG. 8 power supply unit 300 in that the former includes apower supply system 320A for a system, rather thanpower supply unit 320 for a system, and further includes apower supply unit 322A for switching. The remainder is similar to that ofpower supply unit 300, and will not be described repeatedly in detail. -
Power supply unit 320A for the system receives direct current voltage fromAC adapter 310.Power supply unit 320A for the system supplies each component internal tonetwork device 1000 excludingswitch unit 240 andstatus holding unit 400 with operating voltage Vcc. Note thatpower supply unit 320A for the system supplies a voltage supply signal CTPOW corresponding to the operating voltage forcontrol unit 230 to controlunit 230 and tostatus holding unit 400 as well. Note thatstatus holding unit 400 does not use voltage supply signal CTPOW as an operating voltage. Rather,status holding unit 400 monitors the level in voltage of voltage supply signal CTPOW. -
Power supply unit 322A for switching supplies switchunit 240 andstatus holding unit 400 with operating voltage Vcc. In other words, the present embodiment providespower supply unit 300A, in comparison withpower supply unit 300, includingpower supply unit 322A for switching to serve as a power supply unit dedicated to switchunit 240 andstatus holding unit 400. -
Power supply unit 322A for switching has a function utilizing a direct current voltage supplied fromAC adapter 310 to store a predetermined amount of power. More specifically,power supply unit 322A for switching includes a capacitor of a large capacity storing a predetermined amount of power. As such, if a power failure or the like occurs and accordinglyAC adapter 310 does not supply voltage,power supply unit 322A for switching can supplyswitch unit 240 andstatus holding unit 400 with a predetermined level of voltage (or voltage Vcc) for a predetermined period of time T1 (for example of two seconds). Herein, the predetermined period of time T1 is a period of time longer than a period of time required to disable public network communication that is required to disconnect a line ofpublic network 70C (e.g., one second). - After
AC adapter 310 starts to supplypower supply unit 322A for switching andpower supply unit 320A for the system with direct current voltage,power supply unit 322A for switching transmits a power supply reset signal POWRES tostatus holding unit 400. Power supply reset signal POWRES is a signal holding the L level for a predetermined period of time (for example of one second) to initializestatus holding unit 400, and thereafter attaining the H level. Furthermore, power supply reset signal POWRES holds the H level untilAC adapter 310 ceases to supplypower supply unit 322A for switching andpower supply unit 320A for the system with the direct current voltage. - Note that the period of time after
AC adapter 310 starts to supplypower supply unit 322A for switching andpower supply unit 320A for the system with the direct current voltage before an operating voltage thatpower supply unit 322A for switching supplies to each component, as aforementioned, attains a level of Vcc (or the H level) is shorter by a predetermined period of time (for example of two seconds) than the period of time afterAC adapter 310 starts to supplypower supply unit 322A for switching andpower supply unit 320A for the system with the direct current voltage before an operating voltage thatpower supply unit 320A for the system supplies to each component, as aforementioned, attains the level of Vcc (or the H level). - As aforementioned,
communication unit 210A determines whetheranalog telephone 100A is on the hook or off the hook, andcommunication unit 210A sets at the H level or the L level a telephone status signal TELST transmitted to controlunit 230. Telephone status signal TELST of the L level is a signal indicating thatanalog telephone 100A is on the hook. Telephone status signal TELST of the H level is a signal indicating thatanalog telephone 100A is off the hook. -
Control unit 230 transmits a line switching signal TELCH, a line switching signal IPCH and a write signal WR tostatus holding unit 400 in response to a status of each component internal tonetwork device 1000. Line switching signals TELCH and IPCH and write signal WR are signals for controllingstatus holding unit 400. -
Status holding unit 400 operates in response to the plurality of signals transmitted fromcontrol unit 230 and voltage supply signal CTPOW to transmit a switch control signal CHOUT to switchunit 240 for switching a connection status of a line ofswitch unit 240. -
FIG. 2 is a block diagram showing an internal configuration ofstatus holding unit 400. With reference toFIG. 2 ,status holding unit 400 includesflip flop circuits Flip flop circuit 410 includes input terminals S#, D, CLK, R#, and an output terminal Q. Input terminals S#, D, CLK offlip flop circuit 410 receive power supply reset signal POWRES, line switching signal TELCH and write signal WR, respectively. - Input terminal R# of
flip flop circuit 410 receives operating voltage Vcc frompower supply unit 322A for switching. More specifically, input terminal R# offlip flop circuit 410 receives a signal of the H level as long aspower supply unit 322A for switching receives a predetermined level of direct current voltage fromAC adapter 310. Output terminal Q offlip flop circuit 410 outputs an output signal FF1OUT. -
Flip flop circuit 420, as well asflip flop circuit 410, includes input terminals S#, D, CLK, R# and output terminal Q. Input terminals S#, D, CLK, R# offlip flop circuit 420 receive output signal FF1OUT, line switching signal IPCH, write signal WR and voltage supply signal CTPOW, respectively. Output terminal Q offlip flop circuit 420 outputs switch control signal CHOUT.Flip flop circuit 420 operates in accordance with the same operation table (i.e. an operation table T100 as will be described hereinafter) asflip flop circuit 410. - Note that
status holding unit 400 is not limited to the above described circuit configuration. It may have a different circuit configuration as long as it is a circuit configuration capable of performing a process described later. -
FIG. 3 shows operation table T100. With reference toFIG. 3 , operation table T100 indicates “NO.”, which indicates a row number. Operation table T100 indicates “INPUTS”, which indicates each input terminal offlip flop circuits flip flop circuits - Operation table T100 indicates “H”, which indicates that an input terminal of a corresponding column receives a signal of the H level and an output terminal of a corresponding column outputs a signal of the H level. Operation table T100 indicates “L”, which indicates that an input terminal of a corresponding column receives a signal of the L level and an output terminal of a corresponding column outputs a signal of the L level.
- Operation table T100 indicates “L→H”, which indicates that an input terminal of a corresponding column receives a signal having transitioned from the L level to the H level. Operation table T100 indicates “H→>L”, which indicates that an input terminal of a corresponding column receives a signal having transitioned from the H level to the L level. Operation table T100 indicates “H or L”, which indicates that whichever one of the H level and the L level a signal input to an input terminal of a corresponding column may have, an output signal of a corresponding row is not affected in level thereby.
- Operation table T100 indicates “X”, which indicates that whatever level a signal input to an input terminal of a corresponding column may have, an output signal of a corresponding row is determined in level.
- For example, in operation table T100, for the input terminals S#, R#, D, CLK corresponding to a row number “1”, L, H, X, X, correspond, respectively.
- Operation table T100 indicates “NO CHANGE”, which indicates that while the input terminals of a corresponding row each receive a signal having a status as indicated in operation table T100, an output terminal of a corresponding column outputs a signal unchanged in level.
- For example, if output terminal Q outputs a signal of the H level, and input terminals S#, R# each receive a signal of the H level and input terminal CLK receives a signal having transitioned from the H level to the L level, output terminal Q outputs a signal holding the H level.
- Hereinafter, how
network device 1000 operates will be described. Note that even ifnetwork device 1000 is not supplied with operating voltage,analog telephone 100A can use the power ofpublic network 70C to have a telephone call withanalog telephone 100C. In that case,switch unit 240 electrically connectscommunication units network device 1000 will also be referred to as a device operating voltage. - When
network device 1000 is supplied with a sufficient device operating voltage,network device 1000 initially setsanalog telephone 100A ready for having a telephone call withVoIP telephone -
FIG. 4 is an operation waveform diagram, by way of example, for illustrating hownetwork device 1000 operates. With reference toFIG. 4 , prior to time t0,AC adapter 310 is not supplied from the AC power supply with alternate current voltage. More specifically,network device 1000 is not supplied with the device operating voltage and is thus powered off. Whennetwork device 1000 is powered on, then at time t0, supplying the alternate current voltage from the AC power supply toAC adapter 310 starts. - Subsequently at time t1 an operating voltage that
power supply unit 322A for switching supplies to switchunit 240 andstatus holding unit 400 attains the H level (or Vcc). Thus at timet1 switch unit 240 andflip flop circuits status holding unit 400 normally operate. - Furthermore, at time t1,
power supply unit 322A for switching transmits power supply reset signal POWRES tostatus holding unit 400. As has been described previously, power supply reset signal POWRES is a signal holding the L level for a predetermined period of time (for example of one second) and thereafter attaining the H level. Note that at time t1 the operating voltage forcontrol unit 230, i.e., voltage supply signal CTPOW has the L level in voltage. Accordingly at timet1 control unit 230 cannot operate, and line switching signals TELCH and IPCH and write signal WR have the L level in voltage. - Thus, input terminals S#, D, CLK of
flip flop circuit 410 receive power supply reset signal POWRES of the L level, line switching signal TELCH of the L level, and write signal WR of the L level, respectively. Furthermore, input terminal R# offlip flop circuit 410 receives a signal of the H level. - Thus at time t1
flip flop circuit 410 outputs signal FF1OUT having the H level in accordance with each data of row number “1” of operation table T100. - Subsequently at time t2 power supply reset signal POWRES attains the H level. Subsequently at time t3 the operating voltage for
control unit 230, i.e., voltage supply signal CTPOW, attains the H level in voltage. Thus at timet3 control unit 230 becomes normally operable. Furthermore at time t3 each component internal tonetwork device 1000 becomes normally operable. -
Communication unit 210A determines thatanalog telephone 100A is on the hook, andcommunication unit 210A sets telephone status signal TELST at the L level. - In response to telephone status signal TELST having the L level, i.e., when
analog telephone 100A is on the hook, then at timet4 control unit 230 sets line switching signal IPCH at the H level. Ifanalog telephone 100A is not on the hook, then, afteranalog telephone 100A is put on the hook,control unit 230 sets line switching signal IPCH at the H level. - Subsequently at time
t5 control unit 230 sets write signal WR from the L level to the H level. Subsequently controlunit 230 sets write signal WR at the L level. - The process performed at time t5, as described above, causes
flip flop circuit 410 to output signal FF1OUT pulled to the L level at time t6 in accordance with each data of a row number “4” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 410 outputs signal FF1OUT holding the L level in accordance with each data of a row number “6” of operation table T100. - Furthermore the process performed at time t5 causes flip
flop circuit 420 to output switch control signal CHOUT attaining the H level at time t6 in accordance with each data of a row number “5” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 420 outputs switch control signal CHOUT holding the H level in accordance with each data of row number “1” of operation table T100. -
Switch unit 240 thus electrically connectscommunication unit 210A andSLIC 224 together. -
Analog telephone 100A is thus set ready for having telephone call withVoIP telephone network device 1000 is powered on whenanalog telephone 100A is on thehook control unit 230 setsanalog telephone 100A ready for having a telephone call withVoIP telephone - The reason therefore will be described hereinafter. For example when
analog telephone 100A is having a call withanalog telephone 100C,analog telephone 100A is off the hook. Whenanalog telephone 100A is off the hook, performing the above described process interrupts the call betweenanalog telephones analog telephone 100A is on thehook control unit 230 setsanalog telephone 100A ready for having a call withVoIP telephone - Note that if at a time between time t6 and time
t7 analog telephone 100A is put off the hook and a process in whichanalog telephone 100A makes a call toVoIP telephone 100D is performed,control unit 230 receives viacommunication unit 210A,switch unit 240 and SLIC 224 a dial signal A output fromanalog telephone 100A. In that case, dial signal A includes dial information such as a telephone number ofVoIP telephone 100D. - In accordance with dial signal A received,
control unit 230 performs a calling process viacommunication unit 210D forIP network 70D by the telephone number based on dial signalA. VoIP telephone 100D is thus called, Then when the user putsVoIP telephone 100D off the hook,analog telephone 100A andVoIP telephone 100D become communicable with each other.Analog telephone 100A andVoIP telephone 100D thus become communicable with each other. Whenanalog telephone 100A andVoIP telephone 100D are communicable with each other,analog telephone 100A is off the hook. -
Communication unit 210A thus determines thatanalog telephone 100A is off the hook, andcommunication unit 210A sets telephone status signal TELST at the H level. - In response to telephone status signal TELST of the H level, i.e. when
analog telephone 100A is off the hook, then at timet7 control unit 230 sets line switching signal TELCH at the H level. Subsequently at timet8 control unit 230 sets write signal WR from the L level to the H level. Subsequently controlunit 230 sets write signal WR to the L level. - The process performed at time t8 causes flip
flop circuit 410 to output signal FF1OUT attaining the H level at time t9 in accordance with each data of row number “5” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 410 outputs signal FF1OUT holding the H level in accordance with each data of row number “6” of operation table T100. - Furthermore the process performed at time t8 causes flip
flop circuit 420 to output switch control signal CHOUT holding the H level at time t9 in accordance with each data of row number “1” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 420 outputs switch control signal CHOUT holding the H level in accordance with each data of row number “6” of operation table T100. - Herein if at a time between time t7 and time t10 a process in which
VoIP telephone 100B makes a call toanalog telephone 100C is performed,control unit 230 receives viaIP network 70E andcommunication unit 210B a dial signal B output fromVoIP telephone 100B. In that case, dial signal B includes dial information such as a telephone number ofanalog telephone 100C. -
Control unit 230 in response to dial signal B received transmits to LIU 222 a control instruction for performing a calling process forpublic network 70C, and dialsignal B. LIU 222 in response to the received control instruction performs the calling process forpublic network 70C viacommunication unit 210C by the telephone number based on dial signalB. Analog telephone 100C is thus called, and when a user takesanalog telephone 100C off the hook,analog telephone 100C andVoIP telephone 100B become communicable with each other. - Thus
analog telephone 100A andVoIP telephone 100D become communicable with each other andanalog telephone 100C andVoIP telephone 100B become communicable with each other. Note that thatanalog telephone 100C andVoIP telephone 100B are communicable each other means thatcontrol unit 230 is communicable withpublic network 70C and thatanalog telephone 100C andVoIP telephone 100D are communicable each other also means thatcontrol unit 230 is communicable withpublic network 70C. - Once
control unit 230 has become communicable withpublic network 70C, then at timet10 control unit 230 sets line switching signal TELCH at the L level. Subsequently at timet11 control unit 230 sets write signal WR from the L level to the H level. Subsequently controlunit 230 sets write signal WR at the L level. - The process performed at time t11 causes flip
flop circuit 410 to output signal FF1OUT pulled to the L level at time t12 in accordance with each data of row number “4” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 410 outputs signal FF1OUT holding the L level in accordance with each data of row number “6” of operation table T100. - Furthermore the process performed at time t11 causes flip
flop circuit 420 to output switch control signal CHOUT holding the H level in accordance with each data of row number “5” of operation table T100. Subsequently, write signal WR is set from the H level to the L level, whereasflip flop circuit 420 outputs switch control signal CHOUT holding the H level in accordance with each data of row number “6” of operation table T100. - Subsequently if at time t13 a power failure occurs, then the operating voltage supplied by
power supply 320A for the system to each component falls to L level. Accordingly, the operating voltage forcontrol unit 230, i.e., voltage supply signal CTPOW, is also pulled to the L level. Accordingly,control unit 230 outputs line switching signal IPCH having the L level.LIU 222 andSLIC 224 also cease to operate. This puts the line betweenanalog telephone 100C andVoIP telephone 100B on the hook. AfterLIU 222 has ceased to operate, once the time required to disable public network communication has elapsed,analog telephone 100C connected topublic network 70C and public network 70 can no longer communicate a signal therebetween. - Even if a power failure occurs and
AC adapter 310 no longer supplies voltage,power supply unit 322A for switching can supplyswitch unit 240 andstatus holding unit 400 with a predetermined level of operating voltage (i.e., voltage Vcc) for the predetermined period of time T1 (for example of two seconds) longer than the time required to disable public network communication. Thus switchunit 240 andstatus holding unit 400 are also normally operable at time t13. - At time t13
flip flop circuit 410 outputs signal FF1OUT holding the L level in accordance with each data of a row number “7” of operation table T100. - Furthermore at time t13
flip flop circuit 420 outputs switch control signal CHOUT holding the H level in accordance with each data of a row number “3” of operation table T100. Thus switchcircuit 240 does not operate to electrically connectcommunication units - As has been described above,
power supply unit 322A for switching can supplyswitch unit 240 andstatus holding unit 400 with the predetermined level of operating voltage (i.e., voltage Vcc) for the predetermined period of time T1 that is longer than the period of time required to disable public network communication, as counted from whenAC adapter 310 no longer supplies voltage. - Accordingly, when the predetermined period of time T1 elapses from time t13, i.e., when time t14 arrives, the operating voltage supplied by
power supply unit 322A for switching is pulled to the L level. Accordingly, the operating voltage supplied tostatus holding unit 400 is pulled to the L level andstatus holding unit 400 outputs switch control signal CHOUT having the L level. - Furthermore, when
power supply unit 320 for the system supplies a decreasing operating voltage, then beforepower supply unit 320 for the system no longer supplies voltage,switch unit 240 electrically connectscommunication units - Thus when
analog telephone 100A andVoIP telephone 100D are communicable with each other andanalog telephone 100C andVoIP telephone 100B are communicable with each other, and if a power failure or the like occurs andnetwork device 1000 no longer receives the device operating voltage,analog telephone 100A can be prevented from being unintentionally connected toanalog telephone 100C. In other words, unintentional line connection between a plurality of telephones can effectively be prevented. - Hereinafter, a process in which
analog telephone 100A andVoIP telephone 100D are communicable with each other andanalog telephone 100C andVoIP telephone 100B are not communicable with each other (hereinafter this condition will also be referred to as a “single-line connection status”), will be described. In other words, it is assumed that the process in whichVoIP telephone 100B makes a call toanalog telephone 100C, as has been described with reference toFIG. 4 , is not performed. -
FIG. 5 is an operation waveform diagram, by way of example, for illustrating hownetwork device 1000 operates. Note that theFIG. 5 operation waveform diagram is provided when the process in whichVoIP telephone 100B makes a phone call toanalog telephone 100C is not performed. In theFIG. 5 operation waveform diagram for times t0-t9 a process similar to that performed inFIG. 4 for times t0-t9 is performed. Accordingly it will not be described repeatedly in detail. - It is assumed that at a time between time t6 and time
t7 analog telephone 100A is put off the hook and a process in whichanalog telephone 100A makes a phone call toVoIP telephone 100D is performed. This process is similar to that described with reference toFIG. 4 , Accordingly, it will not be described repeatedly in detail. This process allowsanalog telephone 100A andVoIP telephone 100D to be communicable with each other. - Furthermore it is assumed that at time t7 and thereafter a process in which
VoIP telephone 100B makes a phone call toanalog telephone 100C is not performed. - Subsequently if at time t13 a power failure occurs for the sake of illustration, then the operating voltage that
power supply 320A for the system supplies to each component is pulled to the L level. Accordingly, the operating voltage forcontrol unit 230, i.e., voltage supply signal CTPOW, is also pulled to the L level. Accordingly,control unit 230 outputs line switching signals TELCH and IPCH pulled to the L level.LIU 222 andSLIC 224 also cease to operate. Thusanalog telephone 100A andVoIP telephone 100D are no longer communicable with each other. - Even if a power failure occurs and
AC adapter 310 no longer supplies voltage,power supply unit 322A for switching can supplyswitch unit 240 andstatus holding unit 400 with the predetermined level of operating voltage (i.e., voltage Vcc) for the predetermined period of time T1 longer than the time required to disable public network communication. Thus switchunit 240 andstatus holding unit 400 are also normally operable at time t13. - At time t13
flip flop circuit 410 outputs signal FF1OUT holding the H level in accordance with each data of row number “7” of operation table T100. - Furthermore at time t13
flip flop circuit 420 outputs switch control signal CHOUT pulled to the L level in accordance with each data of a row number “2” of operation table T100. Thus switchunit 240 has a function electrically connectingcommunication units time analog telephone 100C is on the hook. Accordingly, whenanalog telephone 100A andVoIP telephone 100D are communicable with each other and if a power failure or the like occurs andnetwork device 1000 no longer receives power,analog telephone 100A can be prevented from unintentionally being connected toanalog telephone 100C. In other words, unintentional line connection between a plurality of telephones can effectively be prevented. - Note that when the predetermined period of time T1 elapses from time t13, i.e., when time t14 arrives, the operating voltage supplied by
power supply unit 322A for switching is pulled to the L level. Accordingly, the operating voltage received bystatus holding unit 400 is pulled to the L level. Accordingly output signal FF1OUT is pulled to the L level. - Hereinafter, a process performed to determine whether a process in which
VoIP telephone 100B makes a telephone call toanalog telephone 100C whenanalog telephone 100A andVoIP telephone 100D are communicable with each other has been performed, will be described. (This process will hereinafter also be referred to as a process performed to determine public network connection.) -
FIG. 6 is a flow chart of the process performed to determine public network connection. With reference toFIG. 6 , step S110 is performed to determine whether there is a request for connection to a public network. More specifically controlunit 230 determines whether a process has been performed in whichVoIP telephone analog telephone 100C connected topublic network 70C. For the sake of illustration, a process in whichVoIP telephone 100B makes a phone call toanalog telephone 100C is performed. - If YES at step S110, the control proceeds to step S120. If NO at step S110, step S110 is repeated.
- At step S120 a line connection process is performed. In this process is performed a process similar to that performed in
FIG. 4 at a time between time t7 through time t10 when the process in whichVoIP telephone 100B makes a phone call toanalog telephone 100C is performed. Accordingly, it will not be described repeatedly in detail. Subsequently, the control proceeds to step S130. - At step S130 a process is performed for storage in the status holding unit. In this process, a process is performed to cause
status holding unit 400 to store information indicating thatcontrol unit 230 is currently communicable withpublic network 70C. More specifically, the process that controlunit 230 performs inFIG. 4 at time t10 and time t11 is performed. Accordingly, it will not be described repeatedly in detail. More specifically,flip flop circuit 410 outputs signal FF1OUT set at the L level. Subsequently, the process performed to determine public network connection ends. - The process performed to determine public network connection allows
communication units control unit 230 communicable withpublic network 70C, i.e., when time t14 arrives, as has been described with reference toFIG. 4 . Furthermore, ifcontrol unit 230 does not become communicable withpublic network 70C, the process performed to determine public network connection (i.e., simply repeating step S110) allowscommunication units FIG. 5 . - Thus in accordance with whether
control unit 230 is communicate withpublic network 70 C control unit 230 performs a process varying when to switch where to connectanalog telephone 100A when a power failure or the like occurs andnetwork device 1000 is accordingly no longer supplied with the device operating voltage. - A process (an IP telephone line connection process) will then be described in which after
network device 1000 is powered on, i.e., after supplyingnetwork device 1000 with the device operating voltage has been started, a status allowing a call to be made withVoIP telephone -
FIG. 7 is a flowchart of the IP telephone line connection process. InFIG. 7 at stepS210 control unit 230 determines whetheranalog telephone 100A is on the hook. If YES at step S210, the control proceeds to step S220. If NO at step S210, step S210 is repeated. Subsequently, the control proceeds to step S220. - At step S220, a line connection process A is performed. In this process is performed a process performed as described in
FIG. 4 at times t4, t5, t6. Accordingly, it will not be described repeatedly in detail. As a result of this process,analog telephone 100A is now ready for having a phone call withVoIP telephone - The IP telephone line connection process can thus effectively prevent for
example analog telephone 100A having a call withanalog telephone 100C from having the call interrupted. - It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modification within the scope and meaning equivalent to the terms of the claims.
Claims (6)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2005-293888 | 2005-10-06 | ||
JP2005293888A JP4369413B2 (en) | 2005-10-06 | 2005-10-06 | Network equipment |
PCT/JP2006/319257 WO2007040132A1 (en) | 2005-10-06 | 2006-09-28 | Network device |
Publications (2)
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US20100157976A1 true US20100157976A1 (en) | 2010-06-24 |
US7944911B2 US7944911B2 (en) | 2011-05-17 |
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US12/088,706 Expired - Fee Related US7944911B2 (en) | 2005-10-06 | 2006-09-28 | Network device |
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US (1) | US7944911B2 (en) |
JP (1) | JP4369413B2 (en) |
CN (1) | CN101283575B (en) |
WO (1) | WO2007040132A1 (en) |
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JP7456207B2 (en) | 2020-03-12 | 2024-03-27 | オムロン株式会社 | Inspection system, inspection method and program |
Citations (5)
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US5179586A (en) * | 1991-03-13 | 1993-01-12 | Northern Telecom Limited | Line interface circuit |
US20030133437A1 (en) * | 2002-01-11 | 2003-07-17 | Richarson John William | Digital subscriber line feature for enabling plain old telephone service on digital lines in the event of a power failure |
US20040218583A1 (en) * | 2003-04-30 | 2004-11-04 | Adan Manolito E. | Computer telephony integration adapter |
US20060221938A1 (en) * | 2005-04-01 | 2006-10-05 | Frank Lin | Voice over IP auto-switching/backup for emergency calls |
US7620825B2 (en) * | 2005-03-28 | 2009-11-17 | Akros Silicon Inc. | Systems and methods operable to allow loop powering of networked devices |
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CN1271901A (en) * | 1999-04-28 | 2000-11-01 | 徐明华 | Computers of public network |
JP2003348226A (en) | 2002-05-24 | 2003-12-05 | Oki Electric Ind Co Ltd | Communication adaptor |
JP2004007314A (en) | 2002-06-03 | 2004-01-08 | Ricoh Co Ltd | Facsimile terminal |
JP2004080483A (en) * | 2002-08-20 | 2004-03-11 | Ntt Communications Kk | Adapter for voice over an internet protocol |
JP4328566B2 (en) | 2003-06-10 | 2009-09-09 | 東北日本電気株式会社 | VoIP switching device |
JP2005026898A (en) | 2003-06-30 | 2005-01-27 | Nec Engineering Ltd | Emergency connection system for ip telephone set |
JP2005039470A (en) | 2003-07-18 | 2005-02-10 | Matsushita Electric Ind Co Ltd | Security apparatus |
JP2005086286A (en) | 2003-09-05 | 2005-03-31 | Sharp Corp | Telephone apparatus |
JP4603417B2 (en) | 2005-05-13 | 2010-12-22 | 株式会社ナカヨ通信機 | Packet telephone system for power failure |
-
2005
- 2005-10-06 JP JP2005293888A patent/JP4369413B2/en not_active Expired - Fee Related
-
2006
- 2006-09-28 CN CN2006800373674A patent/CN101283575B/en not_active Expired - Fee Related
- 2006-09-28 WO PCT/JP2006/319257 patent/WO2007040132A1/en active Application Filing
- 2006-09-28 US US12/088,706 patent/US7944911B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5179586A (en) * | 1991-03-13 | 1993-01-12 | Northern Telecom Limited | Line interface circuit |
US20030133437A1 (en) * | 2002-01-11 | 2003-07-17 | Richarson John William | Digital subscriber line feature for enabling plain old telephone service on digital lines in the event of a power failure |
US20040218583A1 (en) * | 2003-04-30 | 2004-11-04 | Adan Manolito E. | Computer telephony integration adapter |
US7620825B2 (en) * | 2005-03-28 | 2009-11-17 | Akros Silicon Inc. | Systems and methods operable to allow loop powering of networked devices |
US20060221938A1 (en) * | 2005-04-01 | 2006-10-05 | Frank Lin | Voice over IP auto-switching/backup for emergency calls |
Also Published As
Publication number | Publication date |
---|---|
US7944911B2 (en) | 2011-05-17 |
CN101283575A (en) | 2008-10-08 |
WO2007040132A1 (en) | 2007-04-12 |
JP4369413B2 (en) | 2009-11-18 |
CN101283575B (en) | 2012-05-09 |
JP2007104494A (en) | 2007-04-19 |
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